I want to warmly thank the following persons who helped me for
this project :
- Michel Krzesaj, development engineer at the USTL Center of
Computer Resources,
- Stéphane Chachulski and Sebastian Barre, students at the IUT
Department of Informatics, at USTL.

I am also grateful to Mike Golden for his enthusiasm, to Jean
Marie Nys for his kind and irreplaceable technical support and to
my family for their loving support and patience.